This invention relates to a liposuction apparatus and method. More particularly, this invention relates to a liposuction apparatus having an ultrasonic handpiece with an axial suction passage, and is ideally suited for smooth continuous fat removal.
Liposuction, which literally means "fat suction", is a technique that pulls fat out of the body by means of scraping and suction. It can be used to reduce the volume of fat in almost all regions of the body, but is particularly effective in areas such as thighs and abdomen, which contain genetically determined fat not responsive to diet or exercise. Liposuction is currently an established modality in cosmetic surgery, performed by surgeons as an elective operation, and is one of the fastest-growing procedures in medicine.
All existing liposuction devices used in surgery however, cause complications and trauma.
The first reported fat removal procedure was performed in Europe in 1929. Since that time, surgeons have tried common instruments such as surgical knives, scalpels and curettes to remove excess body fat. Also tried were uncommon instruments such as a motorized cutting blade devised by the Fischers, a father-and-son team and early innovators in Italy in or about 1975. Through the years, tools have changed considerably, from sharp knives to blunt cannulas, but fat removal procedures (old or new) are still considered risky and produce inconsistent results. Complications arise mostly due to damaged blood vessels. As a result, organized semi-solid blood clots known as "hematoma" form causing damage to overlying skin and contour irregularities. Other complications, such as seroma formation (the collection of body fluids) can produce infecton and wrinkles. Nerve conduction is also usually affected. Further, too much fat is sometimes removed form the wrong place, resulting in misshaping of the remaining tissue. Lastly, liposuction procedures are time consuming and tedious for both the surgeon and the patient.
The most commonly accepted liposuction technique utilizes a cannula with a blunt closed tip rather than an open tip or a pointed or sharpened tip. This cannula is a metal tube, about the size of a pencil, which is attached to a suction pump. The cannula, with its rounded tip, is sometimes passed through the fat first, without suction, to develop the proper passageways. Then suction is applied and the surgeon continues passing the cannula through the fat tunnels with repeated radial thrusts and on several levels of the tissue. Adipose tissue is aspirated through a hole in the side of the cannula near its distal end. The cannula must be moved back and forth about ten times through each tunnel. Problems associated with this technique are similar to those experienced with the older methods of liposuction. Even with a blunt edge at the distal end of the cannula, fat globules are torn off by both scraping and suction power at the side hole. The bleeding is also similar in amount to that resulting from the use of the older, sharp-edged instruments which cut fat tissue and blood vessels without suction.
The first few minutes of treatment with the blunt cannula technique will usually yield 90% fat and 10% blood. As the treatment continues, an increase in blood content is observed which soon measures 90% blood and 10% tissue. Studies reveal an average of approximately 30% blood in the trap bottle at the end of the procedure. Trauma to the blood vessels ultimately reduces circulation to overlying skin and may cause skin necrosis. Almost all patients have swelling and are often dramatically black and blue for 3-6 weeks. Approximately half will notice some hypesthesia or loss of feeling in the treated area for two to three months. All patients need about six months for improvement to be complete.
Besides causing excess bleeding, current liposuction techniques are also somewhat clumsy in that the surgeon has little sensitivity as to how much fat is being removed during scraping and suction. Consequently, this surgery almost always results in the removal of too much adipose tissue or too little. In addition, a certain amount of fat destroyed by the mechanical action of the cannula is not aspirated. This remaining material can lead to dimpling and other defects. Liposuction that is too aggressive, although achieving a pleasing contour at the end of the procedure, may result in defects that are difficult or impossible to correct. Nevertheless, despite the many risks and drawbacks, thousands of liposuction procedures are performed using the blunt cannula technique.
Fat removal and liposuction has had a checkered history, and for many years was not an accepted modality in the United States. The first reported fat removal through a small incision was by a French surgeon in or about 1929, and resulted in major injuries to blood vessels. Later, a leg had to be amputated. Major developments in liposuction occurred in the late 1970's, and what began as an exploratory technique performed with instruments designed for other purposes became an established modality with novel surgical instrumentation of its own. Interestingly enough, however, none of the present instruments have been accepted by the U.S. Food and Drug Administration.
Although liposuction was developed mainly in Europe, two Americans were early innovators. Wilkerson, practicing in Hawaii in 1968, had acceptable results but abandoned the method because of inadequate instrumentation. Teimourian, working in Bethesda, Maryland in 1976, came upon suction aspiration by accident, and then continued with his new operation with a suction assisted curette. Liposuction was finally popularized by Illouz of France who developed the blunt cannula and the "bicycle spoke" method of removal. He also coined the term "lypolysis."
In 1983, The American Society of Plastic and Reconstructive Surgeons, after evaluating the Illouz procedure in Paris by a blue ribbon committee, "unanimously agreed that suction lipectomy by the Illouz blunt cannula method is a surgical procedure that is effective in trained and experienced hands and offers benefits which heretofore have been available." Currently over 120,000 liposuction operations are performed annually by plastic surgeons in the U.S., and almost an equal number by gynecologists, general surgeons, and ear, nose and throat surgeons. There is also a lipoplasty magazine published by the Lipoplasty Society of North America.
Today there exists a wide variety of cannulas which allow surgeons to work more skillfully. For example, there is a more aerodynamic, bullet shaped tip, or curette-cannula where the suction hole has a sharp edge, or a cannula with a star shaped tip to better loosen the fat, and a spatula-extractor for removing hematoma. Nevertheless, it is still difficult to consistently avoid discoloration, contour irregularities, and cellulite formation which occur as complications ("Liposuctions' Popularity spells Risks," by David Holthaus, Hospitals, February 1988). And as pointed out by Sy Montgomery in "Vacuuming the Fat Away," Working Woman, May 1988, "while it's usually true that after liposuction you'll probably look better in clothes, you might look worse in a bathing suit."
Two of the very earliest uses of "destructive" ultrasound on the body were reported in "Physical Factors Involved in Ultrasonically Induced Changes in Living Systems, Identification of Non-Thermal Effects," by Fry W. J., Acoust, Soc Am 22(6):867,1950; and "An Ultrasonic Unit for the Treatment of Menier's Disease," by Johnson, S. J., Ultrasonics, 5, 173-176, 1967. The latter article described the curing of a middle ear disease earlier, in 1958. The now familiar ultrasonic probes for body tissue removal were developed around 1970 (see U.S. Pat. No. 3,589,363 to Banko and U.S. Pat. No. 3,526,219 to Balamuth) and have been in commercial use for about 15 years. There are perhaps 100 patents describing such ultrasonic devices; U.S. Pat. No. 4,750,902 to Wuchinich lists 40. Nevertheless, at present, there is no commercial use of ultrasound for fat removal liposuction. This is especially surprising since liposuction has been one of the fastest growing medical procedures. A better operative method here would prove both practical and lucrative, as well as probably expand the field. An abdominal liposuction procedure, for example, costs $3,000 to $6,000; a facial procedure on chin and neck, about $2,000, and breast reduction about $2,000. Surprisingly, too, there are no papers in the scientific literature using ultrasonic probes for fat removal, though there are published papers describing the use of ultrasonic probes on almost every other type of tissue, including the liver, pancreas, kidney, testes, stomach, mucosa, cataracts, spinal cord, brain, nerves, rectum, spleen, lung, gastrointestinal tract, arteries, faeces, plasma, collagen, retina and kidney stones. There seems to be a clear need for a new or specialized instrument.
Although an ultrasonic probe for liposuction was granted in 1989 to Parisi, U.S. Pat. No. 4,886,491, there is no evidence that the probe has ever been actually reduced to practice or put into commercial use at least in the United States, despite the great need for an improved liposuction procedure. In accordance with the disclosure of Parisi, fat is melted by localized frictional heat produced by the vibrating probe. Heat however, is dangerous in that it may adversely affect other tissues such as muscle or nerve.
The ultrasonic probe of Parisi is provided at the distal end with a large lateral hole, similar to standard liposuction cannulas. This hole would make his cannula difficult to tune, as well as increase the impedance and require extra power. There is also the risk of cannula breakage, since the hole or holes in the Parisi probes occupy a large percentage of the circumference. The hole or holes are also near a node (point of no movement) where stress is maximum. In order to achieve a 2 mil amplitude at 40 kHz, Parisi's probe as pictured would likely heat an inordinate amount along the length. In addition, the hole or holes at the side of Parisi's probe will scrape tissue and blood vessels similar to the older methods.
Parisi's patent does not address the important question of hematoma or seroma removal. These formations apparently cannot be melted or separated by the method of Parisi.
A prior art tissue removal apparatus and associated method are described in U.S. Pat. No. 4,886,491 issued December 1989. Related patents include U.S. Pat. Nos. 4,223,676, 3,589,363 to Banko, U.S. Pat. No. 3,526,219 to Balamuth, U.S. Pat. No. 4,861,331 to Parisi, and U.S. Pat. No. 4,750,902. Another related patent, which is assigned to one of the same assignees as the present invention is U.S. Pat. No. 4,902,954.
Lastly, in using the probe of Parisi, it would be necessary to move the probe in and out, as well as twist it, in order to collect the separated, melted and emulsified fat.